Ivi 



INTRODUCTION. 



are produced by the same process acting on clusters of crys- 

 talloids of malacolite and other related mineral silicates of 

 secondary origin and characteristic of chemically changed rocks, 

 in Finland, Ceylon, Saxony, New Jersey, &c. Examples of 

 the kind have actually been found in caicite occupying chinks in 

 crystals of spinel. Analogous bodies occur as metaxite in a 

 rock of the same kind ; others, consisting of carbonate of lime, 

 are also common in dolomite near Sunderland. 



(8) "Intermediate skeleton." This corresponds to the calcareous 

 layers alternating with hornblendic augitic and f eldspathic mine- 

 rals, characteristic of silo-carbacid gneisses (Canada, State of 

 New York, Vigan, Pic d'Eridlitz, &c.) ; and it is the same as 

 the calcareous matrix, containing mineral crystalloids, con- 

 stituting hemithrenes. In typical specimens of'Eozoon" the 

 caicite composing this part is plainly a replacement pseudomorph 

 after serpentine. 



(9) The alleged cases of " chambers " and " canal system/ ' 

 preserved in caicite (assuming them to be correct), are explain- 

 able by the fact that this mineral occurs as a pseudomorphic 

 replacement after serpentine and other mineral silicates. 



Geological. 



(10) The presence of {( best-preserved specimens" of " Eo- 

 zoon " in highly crystalline rocks that are chemically altered 

 sediments its absence (the Tudor case we have shown to be 

 untenable) in ordinary unaltered beds its presence in ophites 

 originally igneous (Cornwall), and in dyke-shaped masses of 

 hemithrene originally silacid gneisses (Vosges, Massachusetts, 

 and elsewhere), must be accepted as irreconcilable facts totally 

 subversive of the eozoonal doctrine. 



(11) The occurrence of eozoonal features in crystalline ophites 

 and hemithrenes belonging to the Laurentian, Cambrian, Silu- 

 rian (Connemara, Massachusetts, &c.), and Liassic (Skye) 

 systems, and the fact of their being absent in unaltered rocks 

 of the same and intermediate rock-systems, completely esta- 

 blish their mineral origin. 



